周构建互动游戏

第 2 周：构建互动游戏

第三课：游戏物理与运动

3.1 理解游戏物理

游戏物理涉及模拟现实世界的物理，使游戏更加真实和引人入胜。速度、加速度和重力等基本物理原理可以使游戏中的动作和交互感觉自然。

3.1.1 速度和加速度

• 速度是物体位置的变化率。
• 加速度是速度的变化率。

示例：基本速度运动

import pygame

# initialize pygame
pygame.init()

# screen setup
screen = pygame.display.set_mode((800, 600))
pygame.display.set_caption("basic movement with velocity")

# colors
white = (255, 255, 255)
black = (0, 0, 0)

# player setup
player = pygame.rect(375, 275, 50, 50)
velocity = pygame.vector2(0, 0)

# main game loop
running = true
while running:
    for event in pygame.event.get():
        if event.type == pygame.quit:
            running = false

    # keyboard input for movement
    keys = pygame.key.get_pressed()
    if keys[pygame.k_left]:
        velocity.x = -5
    elif keys[pygame.k_right]:
        velocity.x = 5
    else:
        velocity.x = 0

    if keys[pygame.k_up]:
        velocity.y = -5
    elif keys[pygame.k_down]:
        velocity.y = 5
    else:
        velocity.y = 0

    # update player position
    player.move_ip(velocity)

    # clear screen
    screen.fill(white)

    # draw player
    pygame.draw.rect(screen, black, player)

    # update display
    pygame.display.flip()

pygame.quit()

3.1.2 重力模拟

重力通过向下拉物体来模拟地球上的重力效果，从而为游戏增添真实感。

示例：为下落物体添加重力

import pygame

# initialize pygame
pygame.init()

# screen setup
screen = pygame.display.set_mode((800, 600))
pygame.display.set_caption("gravity simulation")

# colors
white = (255, 255, 255)
black = (0, 0, 0)

# object setup
object = pygame.rect(375, 50, 50, 50)
gravity = 0.5
velocity_y = 0

# main game loop
running = true
while running:
    for event in pygame.event.get():
        if event.type == pygame.quit:
            running = false

    # apply gravity
    velocity_y += gravity
    object.y += velocity_y

    # reset object position if it falls off-screen
    if object.y > 600:
        object.y = 50
        velocity_y = 0

    # clear screen
    screen.fill(white)

    # draw object
    pygame.draw.rect(screen, black, object)

    # update display
    pygame.display.flip()

pygame.quit()

3.2 弹跳和反射物体

要创建动态游戏，通常需要模拟弹跳物体，例如从墙壁反弹的球。

示例：弹跳球模拟

import pygame

# initialize pygame
pygame.init()

# screen setup
screen = pygame.display.set_mode((800, 600))
pygame.display.set_caption("bouncing ball")

# colors
white = (255, 255, 255)
black = (0, 0, 0)

# ball setup
ball = pygame.rect(375, 275, 50, 50)
velocity = pygame.vector2(4, 4)

# main game loop
running = true
while running:
    for event in pygame.event.get():
        if event.type == pygame.quit:
            running = false

    # move ball
    ball.move_ip(velocity)

    # bounce off walls
    if ball.left <= 0 or ball.right >= 800:
        velocity.x = -velocity.x
    if ball.top <= 0 or ball.bottom >= 600:
        velocity.y = -velocity.y

    # clear screen
    screen.fill(white)

    # draw ball
    pygame.draw.ellipse(screen, black, ball)

    # update display
    pygame.display.flip()

pygame.quit()

3.3 迷你项目：弹跳球游戏

目标： 创建一个游戏，让球在屏幕上弹跳，撞到墙壁时改变方向。

3.3.1 代码示例

import pygame

# initialize pygame
pygame.init()

# screen setup
screen = pygame.display.set_mode((800, 600))
pygame.display.set_caption("bouncing ball game")

# colors
white = (255, 255, 255)
black = (0, 0, 0)

# ball setup
ball = pygame.rect(375, 275, 50, 50)
velocity = pygame.vector2(3, 3)

# main game loop
running = true
while running:
    for event in pygame.event.get():
        if event.type == pygame.quit:
            running = false

    # move ball
    ball.move_ip(velocity)

    # bounce off walls
    if ball.left <= 0 or ball.right >= 800:
        velocity.x = -velocity.x
    if ball.top <= 0 or ball.bottom >= 600:
        velocity.y = -velocity.y

    # clear screen
    screen.fill(white)

    # draw ball
    pygame.draw.ellipse(screen, black, ball)

    # update display
    pygame.display.flip()

pygame.quit()

3.4 练习

1. 添加障碍：
   • 引入球可以弹开的固定障碍物。
2. 更改球颜色：
   • 让球每次从墙上弹起时都会改变颜色。

第 4 课：使用声音和音乐

4.1 添加音效和音乐

音效和音乐对于创造身临其境的游戏体验至关重要。 pygame 允许您轻松地为游戏添加声音。

4.1.1 加载和播放声音

• 要在 pygame 中使用声音，您必须首先加载声音文件，然后播放它。

示例：添加声音效果

import pygame

# initialize pygame and mixer
pygame.init()
pygame.mixer.init()

# load sound effect
bounce_sound = pygame.mixer.sound("bounce.wav")

# screen setup
screen = pygame.display.set_mode((800, 600))
pygame.display.set_caption("sound effects")

# colors
white = (255, 255, 255)
black = (0, 0, 0)

# ball setup
ball = pygame.rect(375, 275, 50, 50)
velocity = pygame.vector2(3, 3)

# main game loop
running = true
while running:
    for event in pygame.event.get():
        if event.type == pygame.quit:
            running = false

    # move ball
    ball.move_ip(velocity)

    # bounce off walls and play sound
    if ball.left <= 0 or ball.right >= 800:
        velocity.x = -velocity.x
        bounce_sound.play()  # play sound on bounce
    if ball.top <= 0 or ball.bottom >= 600:
        velocity.y = -velocity.y
        bounce_sound.play()

    # clear screen
    screen.fill(white)

    # draw ball
    pygame.draw.ellipse(screen, black, ball)

    # update display
    pygame.display.flip()

pygame.quit()

4.1.2 背景音乐

• 您还可以添加在游戏过程中持续播放的背景音乐。

示例：添加背景音乐

import pygame

# initialize pygame and mixer
pygame.init()
pygame.mixer.init()

# load and play background music
pygame.mixer.music.load("background_music.mp3")
pygame.mixer.music.play(-1)  # loop indefinitely

# screen setup
screen = pygame.display.set_mode((800, 600))
pygame.display.set_caption("background music")

# colors
white = (255, 255, 255)
black = (0, 0, 0)

# main game loop
running = true
while running:
    for event in pygame.event.get():
        if event.type == pygame.quit:
            running = false

    # clear screen
    screen.fill(white)

    # update display
    pygame.display.flip()

pygame.quit()

4.2 根据事件触发声音

音效可以根据特定的游戏事件触发，例如碰撞或玩家动作。

示例：声音记忆游戏

python
import pygame
import random

# Initialize Pygame and Mixer
pygame.init()
pygame.mixer.init()

# Load sounds
sounds = [pygame.mixer.Sound(f"sound{i}.wav") for i in range(4)]

# Screen setup
screen = pygame.display.set_mode((800, 600))
pygame.display.set_caption("Sound Memory Game")

# Colors
white = (255, 255, 255)
black = (0, 0, 0)

# Generate random sequence of sounds
sequence = [random.choice(sounds) for _ in range(5)]
current_step = 0

# Main game loop
running = True
while running: